66905550 has 72 divisors (see below), whose sum is σ = 181088856. Its totient is φ = 17709120.

The previous prime is 66905537. The next prime is 66905567. The reversal of 66905550 is 5550966.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 70177 + ... + 71123.

It is an arithmetic number, because the mean of its divisors is an integer number (2515123).

Almost surely, 2^66905550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66905550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90544428).

66905550 is an abundant number, since it is smaller than the sum of its proper divisors (114183306).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66905550 is a wasteful number, since it uses less digits than its factorization.

66905550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1122 (or 1114 counting only the distinct ones).

The product of its (nonzero) digits is 40500, while the sum is 36.

The square root of 66905550 is about 8179.5812851270. The cubic root of 66905550 is about 405.9638679453.

The spelling of 66905550 in words is "sixty-six million, nine hundred five thousand, five hundred fifty".